Article thumbnail
Location of Repository

Duplication of modules facilitates the evolution of functional specialization

By Raffaele Calabretta


The evolution of simulated robots with three different architectures is studied. We compared a non-modular feed forward network, a hardwired modular and a duplication-based modular motor control network. We conclude that both modular architectures outperform the non-modular architecture, both in terms of rate of adaptation as well as the level of adaptation achieved. The main difference between the hardwired and duplication-based modular architectures is that in the latter the modules reached a much higher degree of functional specialization of their motor control units with regard to high level behavioral functions. The hardwired architectures reach the same level of performance, but have a more distributed assignment of functional tasks to the motor control units. We conclude that the mechanism through which functional specialization is achieved is similar to the mechanism proposed for the evolution of duplicated genes. It is found that the duplication of multifunctional modules first leads to a change in the regulation of the module, leading to a differentiation of the functional context in which the module is used. Then the module adapts to the new functional context. After this second step the system is locked into a functionally specialized state. We suggest that functional specialization may be an evolutionary absorption state

Topics: Behavioral Analysis, Evolution, Cognitive Psychology, Neural Nets, Robotics, Neural Modelling
Publisher: MIT Press
Year: 2000
DOI identifier: 10.1162/106454600568320
OAI identifier:

Suggested articles


  1. (1998). A case study of the evolution of modularity: towards a bridge between evolutionary biology, artificial life, neuro- and cognitive science. In
  2. (1986). A robust layered control system for a mobile robot.
  3. (1975). Adaptation in Natural and Artificial Systems.
  4. (1970). An Introduction to Population Genetics Theory.
  5. (2000). Asymmetry of configuration space induce by unequal crossover: implications for a mathematical theory of evolutionary innovation.
  6. (1996). Complex adaptations and the evolution of evolvability. doi
  7. (1996). Discontinuity in evolution: how different levels of organization imply preadaptation. In
  8. (1998). Emergence of functional modularity in robots. In
  9. (1970). Evolution by Gene Duplication.
  10. (1998). Evolutionary Biology.
  11. (1995). Evolving mobile robots in simulated and real environments.
  12. (1982). Exaptation - a missing term in the science of form.
  13. (1995). Gene duplication to enable genetic programming to concurrently evolve both the architecture and work-performing steps of a computer program.
  14. (1996). Metazoan complexity and evolution: is there a trend?
  15. (1993). Mobile robot miniaturisation: a tool for investigation in control algorithms. In
  16. (1995). Modular genetic neural networks for 6-legged locomotion.
  17. (1999). Modularity in evolved artificial neural networks.
  18. (1991). Novelty in evolution: restructuring the concept.
  19. (1994). The evolution of functionally novel proteins after gene duplication.
  20. (1983). The Neutral Theory of Molecular Evolution.
  21. (1997). Using emergent modularity to develop control systems for mobile robots.

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.